1. Field of the Invention
This invention relates generally to a method and apparatus for installing a well conductor from a fixed structure along a predetermined path.
2. Prior Art
Systems for installing conductors from multi-well offshore platforms along a deviated path are well known. Such systems enable an operator to obtain maximum bottom hole well spacing from a given fixed surface area. This spacing allows maximum well spacing from a minimum number of platforms.
One installation system is described in U.S. Pat. No. Re. 29,929 to Horvath. In this patent, for example, an irregularity, a so-called "dogleg", is welded to the bottom end of a vertically-extending string of conductor pipe at a slight angle. The irregular bottom initiates a lateral deviation of the downward path taken by the conductor below the mud line. This patent also lists and summarizes other prior art patents relating to the deviation or curvature of pipe conductors.
In drilling operations from a fixed structure, the conductor or drive pipe for a particular slot path may become clogged or damaged below the mud line, or may be proceeding along an interference path with an immobile object (such as another well bore). When this happens, an attempt may be made to correct the conductor pipe problems or salvage the slot by cleanout or shortening the existing conductor. If these measures, which are usually expensive, are unsuccessful, the slot will usually be abandoned as unusable. If sufficient slots are not available, then additional structures will have to be set to fully develop the field.
The present invention offers an alternative solution to this problem by utilizing a new method and apparatus for installing a replacement conductor pipe around said obstruction.
It is, therefore, a general object of this invention to devise a method and apparatus for salvaging a particular slot from a structure wherein the existing conductor for any number of reasons has become unusable.
It is a more particular object of this invention to provide such a method and apparatus wherein the salvage operation has a minimized cost and best success chance factor.
Other objects and advantages of this invention will become apparent from the detailed description to follow, taken in conjunction with the drawings and appended claims.